<template>
    <div class="sidebar">
        <el-menu class="sidebar-el-menu" :default-active="onRoutes" 
            :collapse="collapse" background-color="#324157" text-color="#bfcbd9" 
            active-text-color="#20a0ff" unique-opened @select="handleOpenMenu">
            <template v-for="item in items">
                <template v-if="item.children">
                    <el-submenu :index="item.path" :key="item.path">
                        <template slot="title">
                            <i :class="item.icon"></i><span slot="title">{{ item.title }}</span>
                        </template>
                        <template v-for="subItem in item.children">
                            <el-submenu v-if="subItem.children" :index="subItem.path" :key="subItem.path">
                                <template slot="title">{{ subItem.title }}</template>
                                <el-menu-item v-for="threeItem in subItem.children" :key="threeItem.path" :index="threeItem.path">
                                    {{ threeItem.title }}
                                </el-menu-item>
                            </el-submenu>
                            <el-menu-item v-else :index="subItem.path" :key="subItem.path">
                                {{ subItem.title }}
                            </el-menu-item>
                        </template>
                    </el-submenu>
                </template>
                <template v-else>
                    <el-menu-item :index="item.path" :key="item.path">
                        <i :class="item.icon"></i><span slot="title">{{ item.title }}</span>
                    </el-menu-item>
                </template>
            </template>
        </el-menu>
    </div>
</template>

<script>
    import bus from './bus';
    import appJson from 'public/data/AppMenuData.json';
    export default {
        data() {
            return {
                collapse: false,
                items: []
            }
        },
        computed:{
            onRoutes(){
                return this.$route.path.replace('/','');
            }
        },
        created(){
            // 通过 Event Bus 进行组件间通信，来折叠侧边栏 
            bus.$on('collapse', msg => {
                this.collapse = msg;
            })
            // 对菜单数据初始化处理
            this.handleInitMenuData();
        },
        methods: {
            // 打开菜单的回调
            handleOpenMenu(index, indexPath){
                this.$router.push({path: '/app/' + index});
            },
            // 初始化数据赋值
            handleInitMenuData(){
                if(!!appJson){
                    let data = appJson.list || [];
                    this.items = this.$listToTree(data);
                }
            },
        }
    }
</script>

<style scoped>
    .sidebar{display: block;position: absolute;left: 0;top: 50px;bottom:0;overflow-y: scroll;}
    .sidebar::-webkit-scrollbar{ width: 0; }
    .sidebar-el-menu:not(.el-menu--collapse){width: 200px;}
    .sidebar > ul {height:100%;}
</style>
